The term “obesity” refers to a state of having a larger body weight or a state of having an excessive accumulation of body fat compared to a normal state. Obesity is a contemporary lifestyle disease caused by biased dietary habits, lack of exercise, or lack of sleep. Obesity caused by a metabolic disorder or an endocrine disease is called symptomatic obesity. Either obesity can be a risk factor of diseases such as hyperlipidemia, hypercholesterolemia, hypertriglyceridemia, hypertension, arteriosclerosis, ischemic heart disease, stroke, and arteriosclerosis obliterans. Accordingly, prophylaxis or treatment of obesity can be an effective means for preventing these diseases.
Cholecystokinin (hereinafter, referred to as CCK) is a gastrointestinal hormone secreted from the duodenal mucosal cells by ingestion of a lipid, protein, or other nutrients. This hormone is known to accelerate the enzyme secretion from the pancreas, to contract the gallbladder, and to delay the transfer of gastric contents to the duodenum by closing the pylorus of the stomach (Non-Patent Literature 1). This hormone also directly acts on the central nervous system to suppress the appetite. Thus, the hormone has a physiological function of inducing a feeling of fullness.
By focusing on the physiological effects of CCK, materials having a CCK secretion stimulating activity have been searched, and the uses of the materials have been developed. For example, Patent Literature 1 (Arginine-containing peptide having a cholecystokinin secretion-stimulating activity and food containing the peptide) discloses that a pepsin digestion product of soybean β-conglycinin promotes the CCK-secreting activity in rats to reduce the food intake and that the soybean β-conglycinin is used in a food intake-suppressing food. Non-Patent Literatures 2 and 3 (“Soybean β-Conglycinin Bromelain Hydrolysate Stimulates Cholecystokinin Secretion by Enteroendocrine STC-1 Cells to Suppress the Appetite of Rats under Meal-Feeding Conditions” and “Acute effect of soybean beta-conglycinin hydrolysate ingestion on appetite sensations in healthy humans”) report on that a bromelain hydrolysate of soybean β-conglycinin having a CCK secretion-promoting action suppresses the appetite of rats and human beings. Non-Patent Literature 4 (Development of peptide regulating appetite by controlling a gastrointestinal hormone with high safety) reports on a food containing a bromelain digestion product or peptide of β-conglycinin.
Patent Literature 2 (Composition containing pork-derived peptide having a food intake-suppressing action) discloses a composition containing a peptide having a cholecystokinin secretion-stimulating activity or food intake-suppressing activity prepared by digesting pork or pork-derived protein with pepsin on the basis that the pig-derived peptide promotes CCK secretion and reduces the food intake of rats.
Patent Literature 3 (Pharmacological composition for suppressing appetite) discloses a pharmacological composition for suppressing appetite containing an ingredient showing a cholecystokinin secretion-stimulating action prepared from yeast. This ingredient is low in calorie and has high heat resistance and high enzymolysis resistance.
The list of patent literature and non-patent literature documents as described herein is as follows: